DE1752851A1 - Hydraulic press frame and its manufacturing process - Google Patents

Description

^βί '^; _ν · .- ";" :. ^: - ^{F: i11} Munich, 26 July 1968

Mi! UU; ti // .. Sitinsdorfsti. W.

Patent application

Vickers Limited, Vickers House, Millbank Tower, Millbank, London S.W. 1, England

Hydraulic press frame and process for its manufacture

This invention relates to frames for presses and is concerned with providing inexpensive, lightweight press frames in the form of a weld plate construction, especially for cold metal forming and similar purposes, wherever an effectively guided, high-performance hydraulic press is required.

According to the invention, a press frame is created which a number of plate-like intermediate frames, each delimiting a frame opening and arranged essentially in parallel where the respective openings are right in alignment,

as

109815/0681

as well as two pressure plates, which are through the aligned right Frame openings extend while being spaced from each other are arranged parallel facing each other, the rear sides of the printing plates facing each other along Inner edges of opposing parts of each intermediate frame are attached thereto.

In the whole fretting frame according to the invention, the stress concentration coefficient is very low and the utilization of the construction material very effectively, which means high nominal loads without the risk of failure due to material fatigue and the construction of very light high-performance presses allowed. Purely given size and given weight is that according to the invention Press frame thanks to the absence of a clamped one Joints and areas with high stress concentration stiffer than most frames of other types.

A further reduction in weight and an increase in the load limit (at the expense of rigidity) can be achieved without loss of strength due to the small safety factor that can advantageously be used in the press frame according to the invention induce localized compliance in the areas of hbOhsten Spannungekonzentration of Presaenrahmens and provides favorable residual compressive stresses on at those locations. The"

increases 109815/0681

increases the fatigue strength of the metal in the areas where a high resistance to material fatigue is the greatest is required. No change takes place in the areas of low voltage in which there is a sufficient safety factor is available. This pretensioning method is "far more effective than that commonly used for press frames applied methods, such as the arrangement of pre-tensioned tie rods or wire windings, since the residual stresses that are established are precisely the voltages required to partially neutralize the applied voltages. This is not the case "with other pre-stressing methods in which the residual stress system often bears little resemblance to the applied tensions, especially in the composite face pressure plates, in which the corresponding advantages are most necessary. The mode of operation proposed here can also be used far more cheaply.

The press frame according to the invention has a number of other advantages. In particular, it is with a press frame Given the structural dimensions, a simple matter, the press capacity change by nui c * ie number or thickness the plate-like intermediate frame is changed. This allows a whole series of presses to be manufactured from ordinary ones Stencils and models. This differs from most conventional presses which have a hydraulic booster cylinder in one of the final die castings or makes

intended 109815/0681

is provided, a booster cylinder can also be attached to the printing plate in the present press frame, see above that the cylinder is free of intervening axial stresses, in the case of a single-acting cylinder this is absolutely free of attachments or stress concentrations of any kind. In this way it is possible to use the To increase working stresses in the cylinder itself and to further reduce the weight and manufacturing costs. very high hydraulic pressures are also absorbed more easily, which makes the construction extraordinarily more compact High-performance presses permitted.

In order to better understand the present invention and to illustrate how it can be put into practice, use Reference now, for example, to the accompanying drawings; show in it:

Fig. 1 is a front view of a press frame according to the invention; Fig. 2 is a section along the line A-A of Fig. 1;

Figure 3 is an isometric view, on an enlarged scale, of a detail of Figures 1 and 2 or the appendix of one Sliding surface on the edges of the intermediate frames, this sliding surface reducing one near their ends Has thickness and width;

Fig. 4 10981 5/0681

Pig. Fig. 4 is a view similar to that shown in Fig. 3 showing. however, the use of relaxation slots in the. Shows G-Leitflache with reduced width;

Fig. 5 is a section through part of a press frame, the attachment of a booster cylinder to a Pressure plate is shown; and

6 shows a section through part of a press frame, λ showing other constructions of the intermediate frame which can be used optionally for very large presses.

1 and 2 show a press frame according to the invention for a vertical hydraulic press. The press frame according to the invention has a. Number of plate-like intermediate frames 3, which in this case are four in number and each have a frame opening delimit and run essentially parallel, the frame openings being aligned with one another, as well as two plates 1 and 2, which extend through the aligned frame openings and face each other at a distance from one another in parallel are arranged. The backs of the printing plates 1 and 2 are opposite at 15 along facing inner edges lying parts 4 and 5 of each intermediate frame 3 on it attached.

For this purpose, each intermediate frame 3 consists of an upper and a lower transverse part 4 and 5 together with vertical side parts 6. Parallel sliding surfaces 7 facing one another

109815/0681 for

for guiding the moving parts of the press are arranged essentially perpendicular to the printing plates 1 and 2 and within of the aligned frame openings by welding them to the inner edges of the intermediate frame parts 6, e.g. at 14 are, these edges and parts 6 at right angles to the edges of the printing plates 1 and 2 supporting Parts 4 and 5 extend.

The edges of the intermediate frame members 6 to which the sliding surfaces 7 are attached are designed to obtain a rebate at 13 at each end of the associated surfaces? shaped so that these surfaces 7 are attached to inwardly projecting projections 8 of the side parts 6. As a result, the relevant neutral axes 9 of the cross-section of the rebated side parts 6 are offset inward near the surfaces 7. Due to the axial stresses appearing in these parts 6 under the workload, this eccentrically loaded central section of the side parts tends to bend outwards. This deviation is designed precisely so that it counteracts the tendency of the parts 6 of the intermediate frames 3 to bend inwardly as a result of the bending of the upper and lower transverse parts 4 and 5 in connection with the pressure plates 1 and 2. By suitable selection of the profile of the side parts of the frame and the thickness and the position of the machine sliding surfaces 7 in connection with the elastic properties of the pressure plates 1 and 2 and the transverse parts 4 and 5, the

tendency 109815/0681

Tendency of the side parts and sliding surfaces of the press frame, to bend inward under a load can be reduced to a minimum. This leads to an essential Advantage of the press frame according to the invention over most other press frames, especially on the Area of cold metal forming, in which the exact guidance of moving press components is essential.

FIG. 2 shows a section through the press frame in a perpendicular plane running perpendicular to the intermediate frame 3. As a result of the load distributed on the upper and lower pressure plates 1 and 2, these plates show a tendency to be in the to bend the plane shown in Fig. 2 as a carrier, which is supported at the attachment points of the cross members 4 and 5 of the intermediate frame are. These bends in turn show the tendency, or tend to bend the side parts 6 in this To cause plane, whereby bending of the sliding surfaces 7 take place in the same plane. This effect can also be removed be taken if the transverse space between the adjacent intermediate frame 3 in the section shown in Fig. 2 in connection with the relative dioke of the frame part pairs 5 ', 5' 'etc. in such a way is chosen that the bending moments in the intermediate frame 3 in other levels than in the levels shown in Fig. 1 are turned off.

Of particular importance when reducing the maximum span

nations 109815/0681

The fillets at 11, 12, 13 are missing in the press frame and 16 and the connection points 14 and 15 between the side parts 6 of the intermediate frame or the machine sliding surfaces 7 and the side parts 6 or the transverse parts and pressure plates 4 and 1 and 5 and 2. It is particularly advantageous if the inner contours at points 16 between the cross and the side parts of the intermediate frame evenly with an arch are cut out with a relatively large radius, as can be seen from Fig. 1, i.e. the rebated edge "n der Side parts 6 of an intermediate frame 3 go at the four corners of the frame opening by means of smooth notches with relatively large half diameters in the edges of the cross members 4 and 5 over. This causes the superposition of stress concentrations due to the rounding at 11 and the connection point 15, which is expediently a welded connection, avoided. Similarly, it is essential to provide a smooth transition between the two profiles at the rounded or rebated point 13, in order to avoid an overlapping of the stress concentrations due to the attachment at 14 of the sliding surface 7. In order to reduce the tension effect of this attachment, the thickness 7a or the width of the sliding surface is preferred - which is plate-shaped - near its ends (as shown in Pig. 3) or the width 7b of the surface 7 (as in Fig. 4 shown) and / or slits are provided in the sliding surface as shown at 17 in FIG.

One 109815/0681

One way to detachably attach a press cylinder, such as a hydraulic booster cylinder 18 on the press frame is shown in FIG. This cylinder has a has an ordinary cylindrical construction and is necessarily made of high grade steel and has a very high working tension to its weight and overall diameter to be able to reduce it to a minimum. Pressurized fluid for actuating a (not in the figure shown) movable part of the press is fed to the cylinder through a bore 19 of the end plate 1 of the press. An upper one open end of the cylinder 18 is closed by a disc or an annular piece 20, which is connected to a hydraulic Seal is provided around the lower end of its eye edge which comes into contact with the bore of the cylinder 18. The disk 20 also provides reinforcement for the plate 1 which it is relatively easily fastened, for example by bolts 22 or in any other suitable manner, including a Feed nozzle for connection to the bore 19 for the supply of the pressure medium or a guide bushing for the back of the may contain moving part of the press.

Since the upper region of the cylinder 18 above the seal 21 is not exposed to any internal pressure of the fluid, the Belt tensions there are much lower than those in the lower, high-pressure area, so that it is possible to open the cylinder to attach directly to the top plate 1, with

short 109815/0681

- ίο -

short bolt, as at 23 in Pig. 5 shown. Optionally, a Bevel 24 or a recess 24a can be provided either on the inside or on the outside diameter of the cylinder 18, which has a matching protruding edge of either the disc 20 or a circular ring-shaped retaining ring 24b surrounding the cylinder, which is also attached to the upper plate 1 with bolts is attached. In this way, a very small stress concentration occurs in the cylinder 18, so that high nominal working stresses without the risk of failure due to material fatigue are achievable. In the case of small presses, this can also be achieved by screwing the cylinder onto threads that surround the The outer circumference of the disk 20 is formed above the direction 21.

The process steps of the process described below for the production of a press frame according to the invention, with reference to FIGS. 1-5, consist in that a number of intermediate frames with aligned frame openings are essentially parallel aligned with one another and then the plates 1 and 2 and the sliding surfaces 7 rigidly on the inner edges of the respective intermediate frame parts 4, 5 and 6 within the frame openings are attached to connect the intermediate frames 3 to each other, whereupon the interconnected intermediate frames 3 are pretensioned.

The pre-tensioning of the press frame is done after the

llung 109815/0881

Maintenance, heat treatment and rough machining of the interconnected intermediate frames carried out, the latter machining comprising the drilling of all essential holes in the structure. This pre-tensioning is accomplished by applying a test load between the pressure plates that is approximately 150 io of the normal press frame work load. This stress causes localized bends in the areas of the press frame with maximum stress concentration and produces favorable residual compressive stresses in these areas than normal operating pressure using a rigid load frame. In this way, the press cylinder itself can also be subjected to a slight autofrettage together with its attachment to the frame. For very large presses where constructing a suitable loading frame, the example of the press performance of must ä withstand 150 #, many difficulties will encounter numerous intermediate frame are conveniently made 3 of the press frame as separate units, roughly edited and biased, each unit containing a lot requires lower bias power. These intermediate frames 3 can also be transported separately, which makes assembly much easier. One design approach that enables this manufacturing process is shown in

Fig. 6 1098-5 / 0681

- 12 Fig. 6 shown.

This press frame has a number of intermediate frames 3, each of which has transverse parts and vertical parts as before, only that now each intermediate frame has only one partial plate 25 on each Has the end. These partial plates are - as shown at 26 - fillet-welded to the transverse parts 4, with a simple plate is used for the partial plate or there are optionally a number of elements 27 with a T-shaped cross section by butt welding attached to the cross members - as shown at 28 - to form the sub-panels. The latter construction is permitted better control of the fillet's profile and is preferable. The sub-plates 25 or 27 at each end of the Press frames extend only approximately to the center of the space between each pair of intermediate frames 3. The intermediate frames can therefore be set up next to one another, with the sub-panels either in contact with one another or - as shown in Fig. 6 at 29 - stand a short distance from each other to form the complete press frame. This The press frame is held together by clamping the intermediate frames or the outer or all of the sub-plates 25 or 27 either by bolts 31, tenons (not shown) or by other suitable means on a single plate member be attached. The bolts etc. are attached in the area of the relatively low degree of tension in order to weaken them of the frame, the plate part 30 being

moderately ■ :, i 1098 15/0681

moderately consists of a replaceable wear-resistant plate. A similar construction can also be used for the connection point 14 (Fig. 1) between the side part 6 and the machine sliding surfaces 7. Narrow partial sliding parts, which are similar to the partial plates 25 or 27, are attached to the side parts of each intermediate frame 3 by welding, whereby the entire arrangement by a relatively thin wear-resistant G-m leitflächenplatte held together, which is similar to the plate member 30 and is attached to the different narrow Teilgleitteilen by bolts. the GI Tober egg flat 7 are therefore easily replaceable.

The method described with reference to Fig. 6 for the production of a brake frame consists in that first each intermediate frame 3 is individually pretensioned by applying a load between its sub-plates 25 or 27 which is sufficient to cause localized bends in the areas of maximum stress concentration Cause intermediate frame 3. A number of prestressed intermediate frames 3 are then aligned essentially parallel to one another, with their frame openings, partial plates 25 or 27 and partial sliding parts (which are not shown) in alignment with one another, whereupon the intermediate frames thus aligned by means of plate parts 30 and sliding surfaces - as above described - be attached to each other .

1Ο · Θ15 / Ο $ · 1

OWGlNAU INSPECTED

It should be emphasized that due to the fact that each intermediate frame the press is intended to carry a "certain proportion of the total pressing force independent of the others that various connecting parts - such as the plate part 30 - do not transmit any significant forces between the intermediate frames 3 can and therefore be built relatively easily in terms of weight. You can therefore at any point (and only if required to be attached to the outer intermediate frame 3), on which the stress concentration due to the bolting is acceptable i.e. especially in the areas of low voltage.

The distance between the adjacent plate-like intermediate frames 3 of the frame is also mainly determined by the bending characteristics of the plates in the perpendicular to the press frame Level and determined by the need for uniform loading of the intermediate frame 3. A certain width is in any case required, especially if not all intermediate frames 3 are of the same thickness, with the space between them then used to accommodate pipes or cables, limit switches or additional labor-saving stamps. This bind expediently attached to extensions of the main press plates 1 and 2 or to additional plates attached to the press frame are fixed in the areas of relatively low stresses.

OftenQINAL JNSPECTED:

Claims (10)

- 15 claims 1. Frame for hydraulic presses, characterized by a number plate-like interspaces (3), each of which delimits or has a frame opening, the intermediate frames (3) in the are arranged essentially parallel to one another and the rack openings aligned with each other, and by two plates (1, 2), which are parallel to each other through the aligned openings extend facing, with the rear sides of the plates on facing inner edges of opposing parts (4, 5) of the respective intermediate frame (3) are attached. 2. Press frame according to claim 1, characterized in that opposite lying parts (6) of the respective intermediate frame (3), which are essentially at right angles to the intermediate frame Enteil en (4, 5) extend to which the plates (1, 2) are attached, at their inner edges facing each other Sliding surfaces (7) are provided which are essentially perpendicular to the plates (1, 2). 3. Press frame according to claim 2, characterized in that the edges of the intermediate frame parts (6) provided with sliding surfaces (7) have a profile such that they each form a fold (13) at each end of the associated sliding surface (7) so that the neutral axes (9) of the folded parts (6) in the vicinity of the sliding surfaces (7) of the frame openings 109815/0681 - 16 - Openings are offset inward to prevent the transverse bending of the sliding surfaces (7) and the press frame under load reduce to a minimum. 4. Press frame according to claim 3, characterized in that the thickness of the individual intermediate frames (3) and the distance between adjacent intermediate frame (3) is chosen such that the Bending moments in the press frame - when it is loaded - reduced to a minimum at right angles to the intermediate frame (3) will. 5. Press frame according to claim 3 or 4, characterized in that the folded edges of the parts (6) one with sliding surfaces (7) provided intermediate frame (3) merge at the four corners of the rack opening into the edges of the intermediate frame (3), on which the plates (1, 2) are attached, through smooth cutouts (16), each one relatively have a large radius and are designed such that the maximum working stresses in the press frame to a minimum be reduced. 6. Press frame according to one of claims 2-5, characterized in that that the sliding surfaces (7) are designed in the form of plates, each on corresponding edges of at least two adjacent intermediate frames (3) are attached, the thickness (7a) or width (7b) of each panel being close to theirs end up 10 9 8 15/0681 Ends is reduced uni / or slots (17) in the plate ends are provided to the effect of stress concentrations in the press frame as a result of the attachment of the plates to the concerned Lower the intermediate frame (3) to a minimum. 7. Press frame according to one of claims 2-6, characterized by a press cylinder (18), which is detachably attached at the open end to one Λ of the plates (7), and by a washer (20) which is sealingly inserted within this open end of the cylinder (18) and attached to the plate (1) is attached. 8. Press frame according to one of claims 2-7, characterized in that that individual intermediate frames (3) are each provided with partial plates (25, 27) and / or partial sliding surfaces which work together to form the plates (1, 2) or the sliding surfaces (7) in the Preosen frame. 9. A method for producing a press frame according to one of claims 1-7, characterized in that a number of intermediate frames are aligned essentially parallel to one another, their frame openings being aligned with one another, whereupon oppositely parallel plates and sliding surfaces on the inner edges of the relevant intermediate frame parts are rigidly fastened within the aligned frame openings in order to connect the intermediate frames to each other, after which the interconnected spaces are pretensioned, by doing 109816/0681 by placing a load which is sufficient to the normal press frame workload is applied between the plates to create a localized bend in the press frame areas to bring about maximum stress concentration. 10. A method for producing a press frame according to claim 8, characterized in that each intermediate frame is individually prestressed by applying a load sufficient to a localized Yielding or bending in the intermediate frame areas to bring about the highest stress concentration, between the Partial plates of the frame is applied, whereupon a number of the prestressed intermediate frames are substantially parallel to each other aligned with their frame openings being aligned with one another and the sub-panels aligned with the sub-sliding surfaces, and in that the aligned prestressed intermediate frames are then attached to one another. The patent attorney 109815/0681 ~ T Blank page